Diaphragm



March 18, 19390 A. P. PINKLER DIAPHRAGM Filed July 21, 1925 ATTORNEYPatented Mar. 18, 1930 UNITED STATES ARTHUR R IPINKLER, OF WATERIBURY,CONNECTICUT, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO WM. H. BRISTOL TALKINGPICTURE CORPORATION, OF 'W'ATERBUIRY,

. CONNECTICUT, A. CORPORATION OF CONNECTICUT DIAPHRAGM Application filedJuly 21,

The invention relates to diaphragms for use with sound producing orsound reproducing devices, for example as employed in telephonereceivers, loud spealn'ng receivers, phonographic sound boxes and thelike. It has for its object to provide a diaphragm of sufiicientstrength to take a substantial load yet withal be extremely light so asto be readily responsive to the variations in intensity of the actuatingforce applied thereto. A further object of the invention resides in aconstruction which will admit of the diaphragm responding over a widerange of sound frequencies, that is to say, there will be no sacrificeof quality, as both the high and low notes are equally well reproducednotwithstanding the substantial construct-ion involved.

The nature of the invention, however, will best .be understood whendescribed in connection with the accompanying drawings, in which Fig. 1is an underneath view proved diaphragm.

Fig. 2 is a plan thereof.

- Fig. 3 is a vertical section therethru taken on the line 33, Fig. 1.

Fig. 4 is a vertical transverse section thru a sound box illustratingthe novel manner of of the immounting the improved diaphragm.

Referring to the drawings, the diaphragm is shown as circular in form,as is the usual practice; and is composed of two membersa substantialand more or less rigid member 10, and a flexible non-resonant annularmember 11 carried thereby and secured thereto in any suitable manner asby means of an adhesive, cement or the like. The member 10 may consistof a thin disk of light metal such as aluminum, while the annularmemberll is of non-resonant material such as paper, parchment,celluloid, etc., and which is of greater flexibility, either inherentlyor due to its reduced thickness, than the supporting disk member 10. Thelatter member, further, is formed with a plurality of equidistantlyspaced and radially disposed arms 13 upon which is secured the annulus11 to close over the lntervening spaces. Moreover, it is desirable torender the central portion of the 1925. Serial No. 44,991.

member 10 more rigid than the outer porwith a series of concentriccorrugations 14.

In mounting the novel diaphragm, as in a sound box 15, Fig. 4, the sameis to be held substantially at its circumference between two rings 16and 17 of resilient material, for example soft rubber. Moreover, theupper ring, and which is arranged to bear against the paper annulus, issolid throughout; while the lower ring 17 arranged to be located on theunder side of the diaphragm is preferably made hollow.- The two ringsare designed to clamp the diaphragm over its circumference thru pressureexerted thereon by the two separable members of the sound box 15, whichclamping action may be accomplished by taking up on the screws 18. Whenpressure is thus applied by the screws, the soft rubber material willconform perfectly to the differences in the surface of the diaphragm dueto the notched out portions of the metal supporting member 10, thehollow ring 17 tending. to fill up the spaces in forcing the paper ofthe flexible annulus of the diaphragm against the solid upper ring 16.In this manner, an air-ti ht seal is provided about the diaphragm, oviating any losses of sound waves thru leakage around the circumferenceof said diaphragm.

In thus providing a diaphragm of WhlCh a portion of the supportingmember 10 is notched out as set forth and covered with an annulus oflight, non-resonant material, the weight of same is considerably reducedwithout sacrificing appreciably its strength; and the radial armsresulting therefrom provide for the desired flexibility at the outerportion'of the diaphragm while the corrugations 14 at its centralportion maintain the stiffness ofthe diaphragm at this portion. It willbe noted that this isaccomplished without increase of weight or bymaking up the diaphragm of laminations of different thicknesses anddiameters as has heretofore been proposed. Moreover, in thus providingthe radial arms, a beneficial result is obtained in that all radialstresses in the diaphragm material are substantially eliminated, thediaphragm retaining its original flat condition.

tions; and to this end, the same is provided Three or four concentriccorru ations of a m depth of some .018 have been ound to satisfactorilystiffen the central portion of the diaphragm, a suitable thickness ofwhich, when aluminum is employed, being .020". I have found, also, thatthe paper annulus will give satisfactory results if of an approximatethickness of .0035; and the two members thus combined into a singlediaphragm provide an extremely light member which, however, issufiiciently substantial to Withstand heavy loads such .as arefrequently encountered in connection with the operation of loud speakingreceivers. Furthermore, the diaphragm is constructed to respond both tothe high pitched notes and to the low pitched notes, the former beingtaken care of by arms 13 and the annulus 11 while the central andstifiened corrugated portion 14 responds to the latter.

I claim 1. A diaphragm for sound recording or reproducing units,comprising a thin substantially flat disk having a plurality of integralfree-ended arms extendin radially outward therefrom in the plane 0 saiddisk, and an annular member of non-resonant material and more flexiblethan said disk secured to its arms to cover the intervening free spacesthereof.

2. A diaphragm for sound recording or reproducing units, comprising athin substantially flat disk circularly corrugated at its centralportion and having a plurality of integral free-ended arms extendingradially outward therefrom in the plane of said disk, and an annularmember of non-resonant ma terial and more flexible than said disksecured to its arms to cover the intervening free spaces thereof. 7

3. A diaphragm for sound recordin or reproducing units, comprising athin su stantially flat metal disk having a plurality of integralfree-ended arms extending radially outward therefrom in the plane ofsaid disk, and an annulus of paper secured to said arms to cover theintervening free spaces thereof.

In testimony whereof I afiix my signature.

ARTHUR P. PINKLER.

